I have an 08 JKU. 134k. Installed new Alternator. Immediately upon startup starter will not disengage. Tried restart twice. Same result. Starter is original. Is a new starter needed as well now? Thanks for any advice.
Mtnbkr

 

Do you mean it stays engaged after the engine starts, and the fly wheel spins the starter very fast?

 

No sorry. My engine is actually not starting. I'm charging the battery now. Could that actually be the issue. Thx for the help RONJEX

 

So, what exactly do you mean by " Immediately upon startup starter will not disengage"?

Are you trying to say the starter keeps cranking the engine for a time after you let go of the key?
If so, that's normal behavior for a JK with automatic transmission. It's called Tip-Start. Blip the key over to the start position and the starter will crank until the engine starts, or up to 10 seconds if the engine fails to start.

 

I just joined, and reading this. I have a 07 I just bought (4dr 4wd automatic). Sometimes when I start it the starter stays engaged. Is that what you are talking about with the Tip-Start? No corrections needed.? Its normal.